Dockboards are used in conjunction with loading docks to bridge the gap between the dock and a truck backed in front of the dock to enable material handling equipment, such as a fork lift truck, to move freely between the dock and the bed of the truck. One common form of dockboard is mounted in a pit in the dock and includes a ramp or deck plate which is hinged at its rear edge to the dock and is normally stored in a horizontal or cross traffic position where the ramp is flush with the loading dock. A lip is hinged to the front edge of the ramp and is movable between a downwardly hanging pendant position and an extended position where it forms an extension to the ramp.
To operate a dockboard of this type, the ramp is initially pivoted upwardly to an inclined position, the lip is then extended and the ramp is then lowered until it engages the bed of the truck.
With a horizontally stored dockboard, the overhead door, which encloses the doorway in the dock, is adapted to engage the upper surface of the ramp when the door is in the closed position. With this arrangement, the area between the undersurface of the ramp and the bottom of the pit is not completely weather sealed.
A second type of dockboard is one that is stored vertically within the building so that the overhead door, when in the closed position, will seal against the bottom surface of the pit, to provide a more effective weather seal. With a vertically stored dockboard, the ramp is hinged at its rear edge to a supporting frame and is movable between a generally horizontal operating position and a vertical storage position.
In the conventional vertically stored dockboard, the ramp is moved upwardly to the vertical storage position by a hydraulic cylinder unit or a mechanical counterbalancing system and is locked in the vertical storage position by a mechanical locking mechanism, which can be manually released to enable the ramp to descend by gravity to the horizontal operating position.